package com.outsider.dictlistbea;

import android.support.v4.view.ViewPager;
import android.view.View;

public class ZoomOutPageTransformer implements ViewPager.PageTransformer {

	 private static final float MIN_SCALE = 0.85f;
	    private static final float MIN_ALPHA = 0.5f;

	    public void transformPage(View view, float position) {
	        int pageWidth = view.getWidth();
	        int pageHeight = view.getHeight();

	        if (position < -1) { // [-Infinity,-1)
	            // This page is way off-screen to the left.
	            view.setAlpha(0);

	        } else if (position <= 1) { // [-1,1]
	            // Modify the default slide transition to shrink the page as well
	            float scaleFactor = Math.max(MIN_SCALE, 1 - Math.abs(position));
	            float vertMargin = pageHeight * (1 - scaleFactor) / 2;
	            float horzMargin = pageWidth * (1 - scaleFactor) / 2;
	            if (position < 0) {
	                view.setTranslationX(horzMargin - vertMargin / 2);
	            } else {
	                view.setTranslationX(-horzMargin + vertMargin / 2);
	            }

	            // Scale the page down (between MIN_SCALE and 1)
	            view.setScaleX(scaleFactor);
	            view.setScaleY(scaleFactor);

	            // Fade the page relative to its size.
	            view.setAlpha(MIN_ALPHA +
	                    (scaleFactor - MIN_SCALE) /
	                    (1 - MIN_SCALE) * (1 - MIN_ALPHA));

	        } else { // (1,+Infinity]
	            // This page is way off-screen to the right.
	            view.setAlpha(0);
	        }
	    }

}
